Question

Consider coal (-CH-) (- indicates an aromatic carbon-carbon bond and the average aromatic bond energy is 519 kJ/mol) and cellulose or biomass (-CHOH-) as fuel.

Calculate the amount of energy released per mole and per gram coal burned; calculate the number of moles of carbon dioxide released per 1000 kJ energy released.

Answer 1

An Aromatic compound C-C bond energy = 519 kJ/mol

In general in an aromatic compound,

number of carbon atoms = number of C-C bonds.

so 1 mole of Carbon atoms requires 519 kJ

12 g of Carbon atoms requires 519 kJ

1 g of Carbon atom requires 519/12 = 43.25 kJ

1 mole of Carbon atoms requires 519 kJ

519 kJ energy require to break 1 mole of Carbon atoms

for 1000 kJ energy required 1/519 * 1000 moles of Carbon atoms

                          = 1.9268 moles of Carbon atoms

1 mole of Carbon produces 1 mole of CO2

1.9268 moles of Carbon procuces 1.9268 moles of CO2.